This invention relates to multiple wire cables, and more particularly to small gauge coaxial wiring.
Certain demanding applications require miniaturized multi-wire cable assemblies. To avoid undesirably bulky cables when substantial numbers of conductors are required, very fine conductors are used. To limit electrical noise and interference, coaxial wires having shielding are used for the conductors. A dielectric sheath surrounds a central conductor, and electrically separates it from the conductive shielding. A bundle of such wires is surrounded by a conductive braided shield, and an outer protective sheath.
Some applications requiring many different conductors prefer that a cable be very flexible, supple, or xe2x80x9cfloppy.xe2x80x9d In an application such as a cable for connection to a medical ultrasound transducer, a stiff cable with even moderate resistance to flexing can make ultrasound imaging difficult. However, with conventional approaches to protectively sheathing cables, the bundle of wires may be undesirably rigid.
In addition, cable assemblies having a multitude of conductors may be time-consuming and expensive to assemble with other components. When individual wires are used in a bundle, one can not readily identify which wire end corresponds to a selected wire at the other end of the bundle, requiring tedious continuity testing. Normally, the wire ends at one end of the cable are connected to a component such as a connector or printed circuit board, and the connector or board is connected to a test facility that energizes each wire, one-at-a-time, so that an assembler can connect the identified wire end to the appropriate connection on a second connector or board.
A ribbon cable in which the wires are in a sequence that is preserved from one end of the cable to the other may address this particular problem. However, with all the wires of the ribbon welded together, they resist bending, creating an undesirably stiff cable. Moreover, a ribbon folded along multiple longitudinal fold lines may tend not to generate a compact cross section, undesirably increasing bulk, and may not provide a circular cross section desired in many applications.
The present invention overcomes the limitations of the prior art by providing a cable assembly and method of manufacturing. The method includes providing a core, and wrapping a conductive shield element about the core. An insulating sheath layer is extruded about the core to encompass the shield element, and a multi-wire cable component having ribbonized ends and detached intermediate portions is connected to an end of the core. The core is removed from the sheath to insert the cable component into the sheath. The resulting assembly has intermediate portions of the cable component that are loosely received within the shield and sheath.